1. Field of the Invention
Provided herein are carbamate and thiocarbamate compounds having a polymerizable moiety and one or more free hydroxyl and/or thiol groups. The invention further relates to polymers obtained from the abovementioned compounds, as well as compositions thereof.
2. Description of Related Art
Several catalyzed and uncatalyzed reactions between an isocyanate-containing compound, such as p-methoxyphenyl isocyanate, benzyl isocyanate or 1-naphthyl isocyanate, and 2-mercaptoethanol resulting in the formation of carbamate and thiocarbamate addition products are known and described by Smith et al. in Journal of American Chemical Society, 1959, 81 (1), pages 161-163.
The kinetics of tertiary amine catalyzed reaction of organic isocyanates with thiols is described by Iwakura et al. in Canadian Journal of Chemistry, 1960, 38, pages 2418-2424. The study involved tertiary amine as a catalyst and a mechanism was proposed for the reaction of phenyl isocyanate with 1-butanethiol in toluene solution at 25° C.
The kinetics of triethylamine- and triethylenediamine-catalyzed reaction of phenyl isocyanate with 2-ethylhexanol, phenol, and hexanethiol in benzene at 25° C. are described by Farkas et al. in Industrial & Engineering Chemistry Fundamentals, 1965, 4(1), pages 32-38.
The rates of reaction of a group of phenyl-substituted isocyanates (phenyl isocyanate, nm-toluene diisocyanate and p,p′-diisocyanatodiphenylmethane) and a group of benzyl-substituted isocyanates (benzyl isocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate and 5-t-butyl-1,3-xylene diisocyanate) with ethanol are described by Ferstanding et al. in Journal of American Chemical Society, 1959, 81(18), pages 4838-4842.
U.S. Pat. No. 7,339,020 discloses a process for preparing high-functionality polyisocyanates that have at least three free isocyanate groups and no free isocyanate reactive groups.
U.S. Pat. No. 5,451,695, which is hereby incorporated in its entirety by reference, discloses a polymerizable monomer useful as a starting material for producing high hardness transparent resins. One of the disclosed monomers has the structure:
wherein X is selected from the group consisting of oxygen and sulfur, R2 is selected from the group consisting of a saturated aliphatic residue having or not having at least one member selected from the group consisting of a halogen atom, an oxygen atom, an alicyclic ring, an heterocyclic ring and an aromatic ring, an alicyclic residue, and a heterocyclic residue, n is integer of 1-4. The '695 patent discloses the optional use of a urethane-forming accelerating catalyst such as dibutyl tin diisocyanate.
Several methods exist in literature for the synthesis of carbamates and thiocarbamates by the reaction of isocyanate compounds with compounds containing hydroxyl and/or thiol groups. These methods result in adducts that are devoid of free hydroxyl and/or thiol group(s). Further, polymerizable carbamates and thiocarbamates having free hydroxyl and/or thiol group(s) are expected to have diverse physicochemical properties that can be tailored to meet specific requirements. Therefore, there is a need to develop polymerizable carbamate and thiocarbamate compounds having one or more free hydroxyl and/or thiol groups.